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AWRL6432BOOST: How to evaluate the AWRL6432BOOST EVM angular resolution?

Rick Lu
Prodigy 180 points
Part Number: AWRL6432BOOST
Other Parts Discussed in Thread: AWRL6432

Tool/software:

Hi expert,

The customer has conducted a 2D DBF (Digital Beamforming) angle evaluation based on the AWRL6432 EVM (Evaluation Module).

From the simulation results, it can be seen that the simulated result for the AWRL6432 EVM is 31.2°(-3dB).

If we evaluate it by using the longest equivalent aperture, the equivalent angular resolution of the AWRL6432 EVM should be 2/4 * 50.8° = 25.4°.

My questions are :

Why is the simulated result 31.2°?

Currently, I am using a 2D DBF array simulation and calculating the degrees corresponding to the -3dB attenuation of the main lobe in the azimuth/elevation dimension as half of the resolution. Is this method reasonable?

thank you,

Rick

  • 0
    TI__Mastermind 40855 points

    Hi, Rick:

    The definition of angle resolution is when you have two object at the same range bin, the minimum angle difference that can separate the two target apart.    The theoretically formula for angle resolution is pi/(2*(N-1)).

    I am not sure about your below statement, can you give me more information?

    "If we evaluate it by using the longest equivalent aperture, the equivalent angular resolution of the AWRL6432 EVM should be 2/4 * 50.8° = 25.4°."

    Best,

    Zigang

  • 0 in reply to zigang Yang
    TI__Prodigy 180 points

    Hi Zigang,

    This calculation method uses the ULA method, where d is λ/2. Δθ≈0.886*λ/N*d

    The longest aperture of 6432 in the azimuth direction is 4, so the angular resolution should be​  2 / 4 * 57.3 * 0.886 ≈ 25.4°.

    From the simulation results, it can be seen that the simulated result for the AWRL6432 EVM is 31.2°(-3dB).

  • 0 in reply to Rick Lu
    TI__Mastermind 40855 points

    Hi, Rick:

    I have reached system team for help.  We will get back to you as soon as possbile.

    Best,

    Zigang

  • 0
    TI__Intellectual 790 points

    Hello Rick.

    The angle resolution formula is originally:

     - lambda/(N * d * cos(theta)) (in radians)

    where lambda is wavelength, N is the number of elements, d is the antenna separation, and theta is the angle of arrival. 

    When the antennas are separated by d=lambda/2 and if we measure the resolution at boresight (theta = 0), the resolution above becomes:

     - 2/N (in radians) (please also check out the application note at www.ti.com/.../swra554a.pdf

    which can be calculated as:

    - 2/4 * 180°/pi = 2/4 * 57.3° = 28.65°

    The difference in your simulations are most probably due to the difference in the ratio of lambda/d in the original equation. If you set the lambda of your chirp configuration slightly off from the physical antenna separation d, that difference can occur (i.e., if the lambda/d ratio is not exactly 2).

    Regards.

    Muhammet